The role of NAG (N-acetyl-beta-D-glucosaminidase) in the diagnosis of kidney disease including the monitoring of nephrotoxicity.

The assay of urinary N-acetyl-beta-D-glucosaminidase (NAG) provides an early indication of tubular dysfunction resulting from renal disease or nephrotoxic damage. False positives are rare and its activity remains high during active disease or a sustained toxic insult but falls to normal levels on recovery or removal of the toxin. Urinary NAG activity can be used in conjunction with other tests to assess disease activity and prognosis. The assay of NAG isoenzymes increases the diagnostic potential of this test while the availability of dipsticks and simple assay kits will allow its use outside the laboratory.